A large-scale cold plasma jet: generation mechanism and application effect

Atmospheric pressure cold plasma jets(APCPJs) typically exhibit a slender, conical structure,which imposes limitations on their application for surface modification due to the restricted treatment area. In this paper, we introduce a novel plasma jet morphology known as the large-scale cold plasma jet(LSCPJ), characterized by the presence of both a central conical plasma jet and a peripheral trumpet-like diffuse plasma jet. The experimental investigations have identified the factors influencing the conical and the trumpet-like diffuse plasma jet, and theoretical simulations have shed light on the role of the flow field and the electric field in shaping the formation of the LSCPJ. It is proved that, under conditions of elevated helium concentration, the distributions of impurity gas particles and the electric field jointly determine the plasma jet’s morphology. High-speed ICCD camera images confirm the dynamic behavior of plasma bullets in LSCPJ, which is consistent with the theoretical analysis. Finally, it is demonstrated that when applied to the surface treatment of silicone rubber, LSCPJ can achieve a treatment area over 28 times larger than that of APCPJ under equivalent conditions. This paper uncovers the crucial role of impurity gases and electric fields in shaping plasma jet morphology and opens up the possibility of efficiently diversifying plasma jet generation effects through external electromagnetic fields. These insights hold the promise of reducing the generation cost of plasma jets and expanding their applications across various industrial sectors.

Lithium metal anodes: Present and future

Commercial lithium-ion(Li-ion)batteries based on graphite anodes are meeting their bottlenecks that are limited energy densities.In order to satisfy the large market demands of smaller and lighter rechargeable batteries,high-capacity metallic Li replacing low-specific-capacity graphite enables the higher energy density in next-generation rechargeable Li metal batteries(LMBs).However,Li metal anode has been suffering from dendritic problems,interfacial side reactions,volume change and low Coulombic efficiency.Therefore,performance enhancements of Li metal anodes are rather important to realize the high energy density characteristic of metallic Li.In this review,the annoying Li dendrite growth,unstable reaction interface and practical application issues of Li metal anodes are summarized and detailedly discussed to understand the current challenges concerning Li metal anodes.For overcoming such remaining challenges,the corresponding strategies and recent advances are covered and categorized.Finally,we discuss future opportunities and perspectives for developing high-performance Li metal anodes.

Influence of non-uniform electric field distribution on the atmospheric pressure air dielectric barrier discharge

The dielectric barrier discharge(DBD)in air at atmospheric pressure is not suitable for industrial applications due to its randomly distributed discharge filaments.In this paper,the influence of the electric field distribution on the uniformity of DBD is theoretically analyzed and experimentally verified.It is found that a certain degree of uneven electric field distributions can control the development of electron avalanches and regulate their transition to streamers in the gap.The discharge phenomena and electrical characteristics prove that an enhanced Townsend discharge can be formed in atmospheric-pressure air with a curved-plate electrode.The spectral analysis further confirms that the gas temperature of the plasma produced by the curved-plate electrode is close to room temperature,which is beneficial for industrial applications.This paper presents the relationship between the electron avalanche transition and the formation of a uniform DBD,which can provide some references for the development and applications of the DBD in the future.

Generation characteristics of a metal ion plasma jet in vacuum discharge

To improve the performance of a metal ion plasma jet in vacuum discharge, an anode-insulated cone-cylinder electrode with insulating sleeve is proposed in this paper. Discharge characteristics and generation characteristics of plasma of the electrode are investigated, effects of diameter of insulating sleeve, variety of cathode material and length of the insulating sleeve on characteristics of metal ion plasma jet are discussed. Results indicate that a directional and steady plasma jet is formed by using the novel electrode with insulating sleeve under high vacuum conditions. Moreover, the properties of metal ion plasma jet are improved by using the aluminum cathode and thin and long insulating sleeve. The study provides strong support for research of vacuum metal ion plasma thruster and ion implantation technology.

Influence of Ti_(3)C_(2)T_(x)(MXene)on the generation of dielectric barrier discharge in air

The formation of homogeneous dielectric barrier discharge(DBD)in air is a key scientific problem and core technical problem to be solved for the application of plasmas.Here,we report the effect of two-dimensional(2D)nanomaterial Ti_(3)C_(2)T_(x)(Tx=-F,-O and/or-OH)on regulating the electrical discharge characteristics.The field emission and weak bound state property of Ti_(3)C_(2)T_(x)can effectively increase the seed electrons and contribute to the generation of atmospheric pressure homogeneous air DBD.The electron avalanche development for the uneven electrode structure is calculated,and the discharge mode transition is modeled.The comparative analyses of discharge phenomena validate the regulation of Ti_(3)C_(2)T_(x)on the discharge characteristics of DBD.The light emission capture and the voltage and current waveforms verify that the transition of Townsend discharge to streamer discharge is effectively inhibited.The optical emission spectra are used to characterize the plasma and confirm that it is in a non-equilibrium state and the gas temperature is at room temperature.This is the first exploration of Ti_(3)C_(2)T_(x)on the regulation of electrical discharge characteristics as far as we know.This work proves the feasibility of Ti_(3)C_(2)T_(x)as a source of seed electrons to form homogeneous DBD,establishing a preliminary foundation for promoting the application of atmospheric pressure non-equilibrium plasma.